68 Elephants killed in Congo park using Machine Guns and Chainsaws.

RABAT, Morocco (AP) — One of Africa’s oldest national parks is under attack “from all fronts,” its director said Friday after 68 elephants were slaughtered in two months by poachers, some of whom shot them from helicopters.

Garamba National Park in the Democratic Republic of Congo is under constant assault by renegade Congolese soldiers, gunmen from South Sudan and others. And this is just a slice of the poaching carnage: international wildlife regulators say 20,000 elephants were killed in Africa alone in 2013.

The Johannesburg-based African Parks group, which manages Garamba, said since mid-April, the 5,000-square kilometer (1,900-square mile) park has faced an onslaught from several bands of poachers who have already killed 4 percent of its elephants.

“The situation is extremely serious,” Garamba park manger Jean-Marc Froment said in the statement. “The park is under attack on all fronts.”

Conservationists say a thriving ivory market in Asia is helping to fuel the worst poaching epidemic of African elephants in decades.

A 2012 census found just 2,000 elephants in Garamba Park, down from 20,000 in the 1960s.

One group of poachers in the park is shooting the elephants from a helicopter and then chopping off their tusks with chain saws, removing the elephants’ brains and genitals as well. In some cases the attacks seem indiscriminate, killing baby elephants that do not yet possess the valuable ivory tusks.

African Parks, which runs seven parks in six countries in cooperation with local authorities, said the poachers include renegade elements of the Congolese army, gunmen from South Sudan and members of the Lord’s Resistance Army, a militant rebel group whose fugitive leader Joseph Kony is an alleged war criminal.

In one skirmish with poachers, park guards had to protect themselves from hand grenades thrown by Southern Sudanese poachers, some of whom were wearing military uniforms.

Froment singled out in particular elements of the LRA, which is notorious for kidnapping children and using them as soldiers. In 2009, the group attacked the park’s headquarters, killing 15 employees and family members.

The group is known to be in the heavily forested areas around Garamba park.

A spokeswoman for African Parks, Cynthia Walley, said the heavy vegetation and the large concentration of elephants in the park have made it a target for poachers.

“It’s pretty well documented that Garamba is one of the few remaining places where you get these large herds of elephants,” she said. “The supply of elephants in some parts of Africa for poachers has diminished. So in areas where you are protecting elephants you become a target.”

She said African Parks, which has run Garamba in cooperation with the Congolese parks authority since 2005, beefed up its forces in anticipation of increased poaching this year but found recent spike to be “unprecedented.”

In addition to Congolese and park forces, units from the U.S. military’s African Command are supporting the anti-poaching efforts, African Parks said.

In recent years, the U.N. has warned that armed groups in Africa have been turning to ivory poaching to fund their struggles. Many are also using the more sophisticated weapons that flowed out from Libya after the fall of Moammar Gadhafi in 2011.

The Geneva-based Convention on International Trade in Endangered Species of Wild Fauna and Flora said Friday that 20,000 elephants were killed in 2013 in Africa, but overall poaching was on the decline due to better law enforcement.

The spike in attacks on Garamba suggests that poachers may be shifting to different targets. Poaching has been down in Chad, for instance, while it has been on the rise in Central African Republic, which is being wracked by a civil war.